The shipment of products that must have their temperature maintained within a specified temperature range is one of the fastest growing market segments in the modern shipping industry. This growth is driven by a number of factors including widespread concerns about safety in the cold food distribution chain, increasing numbers of pharmaceutical and life sciences products which must have their temperature maintained within certain limits, the rapid growth in high-value specialty chemicals such as those used in the semiconductor industry, the increasing number of sophisticated medical tests which require the shipment of patient specimens to an external laboratory, the increased number of clinical trials associated with new pharmaceutical discovery and the increased delivery of products directly to the customer as a result of Internet ordering.
This field is generally referred to as controlled temperature packaging (CTP). CTP can be segmented by the target temperature range, namely: frozen (e.g., below −15° C.); 2° C. to 8° C.; and less than ambient (e.g., less than 30° C.). Controlled temperature packaging may also encompass targeted temperatures in the ambient range (e.g., 15° C. to 30° C.), or above ambient, such as about 37° C. (e.g., human body temperature). Other specialty applications require different temperature ranges, such as specialty ice cream (e.g., below −40° C.), swine semen (e.g., 15° C. to 19° C.), and high end chocolates (e.g., 12° C. to 18° C.) as examples.
In addition, CTP may be segmented by container size, for example: greater than pallet; one cubic foot to pallet; and less than one cubic foot. Containers having a size greater than pallet are typically cooled or heated mechanically and the shipment times are typically from days to many weeks. The one cubic foot to pallet size segment is dominated by systems using ice and/or thermally conditioned (e.g., cooled) water in the form of gel packs and/or dry ice as a coolant. Gel packs typically include a small quantity of super absorbent polymer (SAP) or carboxymethylcellulose (CMC) that is added to the water to dramatically increase its viscosity to help keep the shape of the pack and to reduce leakage. The containers are typically insulated using expanded polystyrene (EPS) or polyurethane (PU). The market segment for containers less than one cubic foot in size has been limited due to the inability of EPS and PU systems to maintain uniform temperatures in this size range except for very short durations (e.g., less than one day). The problem is especially difficult for products which are not frozen and require both cold and hot side protection, e.g., that must be kept within a specific temperature range.
Although many basic ice/EPS systems are in use for cooling shipping containers, there is a wide variation in quality and performance of the packaging depending on the value of the product and the sensitivity of the product to temperature fluctuation. A relatively simple system includes a cardboard box into which EPS sheet has been cut and placed. The container is then filled with dry ice in which, for example, frozen fish is shipped. A more sophisticated approach is a validated system consisting of custom molded EPS forms in a rigid box with both frozen and thermally conditioned gel packs, the combination of which has been tested through a range of temperature cycles for specified thermal properties. Such a validated system can be used for shipping pharmaceuticals. For example, many pharmaceutical products, such as vaccines and antibodies, must be maintained at 2° C. to 8° C.
An example of the foregoing system is illustrated in U.S. Pat. No. 5,924,302 by Derifield issued on Jul. 20, 1999. This patent illustrates a shipping container that includes a plurality of cavities adapted to receive a coolant (e.g., gel packs) that surround a chamber that is adapted to receive an item to be shipped.